Green urine is almost always caused by something you ate, a medication you’re taking, or a supplement in your routine. It looks alarming, but in most cases it’s harmless and clears up on its own within a day or two. Less commonly, green urine can signal a urinary tract infection or a liver problem, especially if other symptoms come along with it.
How Urine Turns Green
Your urine is normally yellow because of a pigment called urochrome, a byproduct of your body breaking down red blood cells. When you introduce a blue or blue-green substance into your system, whether from food, a dye, or a medication, it mixes with that yellow pigment. Yellow plus blue equals green. That’s the basic chemistry behind nearly every case of green urine.
Foods and Supplements That Cause It
Asparagus is the most well-known culprit. It can give urine a greenish tint along with that distinctive smell often compared to rotting cabbage. Artificially colored foods and drinks, particularly those with blue or green dyes, can do the same thing. Think brightly colored sports drinks, popsicles, cake frosting, or candy.
B vitamins are another common cause. They can turn urine a fluorescent yellow-green that looks startling in the toilet bowl. If you recently started a B-complex supplement or a multivitamin with high B-vitamin content, that’s likely your answer. The color change is harmless and just means your body is excreting what it doesn’t need.
Medications That Change Urine Color
A surprisingly long list of medications can turn urine green. Some of the more common ones include amitriptyline (a tricyclic antidepressant), indomethacin (an anti-inflammatory), cimetidine (a heartburn drug), promethazine (an anti-nausea medication), and the water pill triamterene. Propofol, the anesthetic used during surgeries and procedures, is also known for it. Your liver breaks propofol down into compounds that, once filtered through your kidneys, give urine a green color.
If you recently started a new medication or had a medical procedure and noticed the color change shortly after, the medication is the most likely explanation. The green color typically fades once the drug clears your system.
Medical Dyes and Procedures
Methylene blue is a medical dye used during certain surgeries and diagnostic tests. Surgeons use it to highlight lymph nodes during cancer operations, and doctors sometimes apply it during endoscopies to identify abnormal or precancerous cells in the esophagus. If you’ve had any procedure involving this dye, expect blue-green urine (and possibly blue-green stool) for a short time afterward. The blue dye blends with the natural yellow of your urine to create the green appearance.
Urinary Tract Infections
Certain bacteria, particularly a type called Pseudomonas, produce green pigments as they grow. A Pseudomonas urinary tract infection can tint your urine green. This is less common than dietary or medication causes, but it’s worth considering if the green color comes with other symptoms: burning when you pee, needing to go more often or more urgently, foul-smelling urine, pelvic or lower back pain, or fever and chills. If you’re experiencing any of those alongside the color change, you likely need a urine test and antibiotics.
Liver and Bile Problems
This is the least common but most serious possibility. Your liver produces a green pigment called biliverdin as part of its normal process of breaking down old red blood cells. Biliverdin is usually converted quickly into bilirubin (a yellow pigment) and excreted through bile. When bile flow gets blocked, whether by gallstones, liver disease, or another obstruction, biliverdin can build up and spill into your urine, turning it green.
A condition called obstructive jaundice can cause this. The green urine would come alongside more obvious and concerning symptoms: fever, abdominal pain, itching, nausea, and possibly yellowing of the skin or eyes. This is a medical emergency. If you have green urine paired with abdominal pain and fever, get immediate medical attention.
There is also an extremely rare genetic condition called hyperbiliverdinemia, where elevated biliverdin levels cause green discoloration of the skin, urine, and even breast milk. It’s associated with biliary obstruction and liver failure, and green urine is present in virtually every case. But this condition is so uncommon that it’s far down the list of possibilities.
How Long Green Urine Lasts
If the cause is food, a supplement, or a medication, the green color typically resolves within 24 to 48 hours after you stop consuming whatever caused it. Drinking more water helps dilute the pigment and flush it through faster. For medical dyes like methylene blue, give it a day or two after your procedure.
If your urine stays green for more than a couple of days with no clear explanation, or if it comes with pain, fever, or other new symptoms, that’s worth a conversation with your doctor. In the absence of those red flags, you’re most likely looking at a harmless side effect of something in your diet or medicine cabinet.